Prof. Alessandro Nanussi
• Born in 1968, classical high school diploma, graduated in Dentistry in 1993, master’s degree in Sports Dentistry, he is Past-president of the Italian Society of Sports Dentistry and of the Italian Association of Gnathology and Orofacial Pain, founding member and council of the International Academy of Innovative Dentistry, council and representative of the scientific and educational committee of the European Association for Sport Dentistry.
• Already a contract professor of statistical analysis of epidemiological data, he holds the elective course “Analog and virtual articulators”, University of Milan-Bicocca, invited lecturer at the University of Chieti-Pescara, Perilugia and Palermo, lecturer in charge of the course Clinical Dentistry and Gnathology at the SOMA Osteopathic Institute in Milan.
• Associated with Prof. Cristian Coraini at Studio Skysmile in Milan. Contact person until 2021 for the Craniomandibular Biomechanics and Sports Dentistry Service at the Italian Stomatological Institute in Milan.
• Author of international publications, Co-author of the text “Dentistry and Sport”, published by Edi-Ermes, winner with Prof. Cristian Coraini and Mr. Luca Vailati of the International Prize on Occlusion, at the 15th ICP World-Congress in 2013, speaker at national and international Congresses of gnathology, prosthetics and sports medicine and at the 2024 Congress of the International Olympic Committee.
• He has been dealing with functional analysis in gnathology, prosthetics and sports dentistry in an interdisciplinary field for more than thirty years.
Assuming that the preliminary clinical evaluation must help to understand whether the stomatognathic and general context of the patient exposes him to the risk of occlusal overload, the individualized management of functional parameters and a rigorous protocol for managing occlusal forces still represent the essential starting point in the design and execution of a prosthetic therapy, especially if complex.
The pre-evaluation mock up is therefore ennobled by a simple preliminary evaluation of the aesthetic impact, to simulation and pre-visualization of the future intermaxillary relationship, which must therefore integrate not only with the lips and face of the patient but also with the necessary static and dynamic functional integration.
The orientation of the models, digitally acquired with a virtual face bow (JMA-Optic, zebris Medical), allows for high predictability of movement, with the creation of an occlusal design and immediately functionalized anatomies. If it is absent, essential spatial information is lost which, in analog work, is used by protocol.
The use of a digital workflow that exploits the use of anatomical data and the patient’s movement, allows the matching of the Smile Design with the three-dimensional anatomical design of the dental elements and the relative intercuspidation points and disclusion paths, according to standardized protocols designed to make it applicable to daily practice.
In this way, the patient’s function will be respected by avoiding overloads (which may affect the integrity and duration of the prosthetic restoration), the control of static and dynamic occlusal contacts, the rigorous management of disclusion paths and occlusal forces, preventing failure due to collapse of the structure or of the prosthetic pillars involved. In the absence of a correct adaptation of the prosthetic to the functional needs of the patient, adaptive motor strategies may appear that may exceed or exhaust the compensation and tolerance capacities of the subject in predisposing contexts: this results in the possible appearance of symptoms ranging from discomfort, to pain, to functional limitation, in particular in patients with dysfunctional symptoms of TMD or with parafunction associated with emotional factors.
There are several areas in which the advantage of the REAL MOVEMENT application bow (JMA-Optic, zebris Medical) is perceptible, simple and effective to summarize them as follows:
- Predictability of movements in the orientation of the models
- Integration with smile design
- Respect for function
- Management of forces
- Occlusion survey
- Reproducibility of the functionalized anatomy of temporary restorations
- Integration of cephalometry – digital orthodontic set-up
- Planning on the “virtual patient”
- Transition from the articulator to REAL MOVEMENT
- Prevention of failure due to overload and compromise during treatment.
In the image (Fig. 1), an example of an aesthetic and functional approach made possible by the functional predictability determined by the data acquired with a digital face bow.
The possibility of having the “virtual patient” available also makes the variations in vertical dimension or the recovery of the reference intermaxillary position predictable, simplifying the prosthetic project thanks to the possibility of simulating different hypotheses in a virtual environment. The overcoming of the concert of “articulator” intended as a simulator and the most faithful replica possible of the patient’s movement, occurs thanks to the acquisition of real movements and the correct orientation of the upper arch with respect to the ideal rotation axis of the temporomandibular joints: it is no longer a question of approximation but of faithful replication of anatomy and function. The articulator intended as an irreplaceable tool in an analog environment, can however be used by exploiting the digitally acquired data.
The images (Fig. 1) illustrate the clinical and functional evaluation of a case of anterior laminate veneers in which the patient’s needs did not coincide with the operational feasibility, due to the anterior overloads caused by the dental class, the lack of vertical dimension and the absence of the left canine guide which determined an overload on dental element 22, with risk of mechanical damage and/or migration. Element 12 is aesthetically dominant.
A preliminary orthodontic treatment with upper transparent aligners and lower fixed orthodontics allowed to restore the left canine guide and reduce the anterior occlusal forces.
The analysis of the arches using the acquisition of the digital face bow and the real mandibular movement, allowed to accurately predict the reciprocal movement of the arches. A rehabilitation was therefore designed that respected the functional needs, the biomechanical resistance of the artifact, the joint function.
The resulting smile design was therefore not a simple (and often unrealizable) aesthetic visualization, but the two-dimensional expression of a 3D-rehabilitation project. Consequently, the aesthetic/functional mock-up was almost immediately appreciated and comfortable, and the reproducibility of the volumes (re-scanned) guaranteed the highly predictable final result.
The video shows the measurement possibilities and features of the zebris Jaw Motion Analyzer System – JMA-Optic. The measurement sequence includes the input of the bipupillary and mouth position, the manual and physiological determination of jaw relations, options for dynamic occlusion analysis through to smile design and export to external CAD systems.
SOURCES
1) Goldstein G, Goodacre C. Selecting a Virtual Articulator: An Analysis of the Factors Available with Mechanical Articulators and their Potential Need for Inclusion with Virtual Articulators. J Prosthodont. 2023 Jan; 32(1):10-17.
2) Lepidi L, Galli M, Mastrangelo F, Venezia P, Joda T, Wang HL, Li J. Virtual Articulators and Virtual Mounting Procedures: Where Do We Stand? J Prosthodont. 2021 Jan; 30(1):24-35.
3) Walker PM. Discrepancies between arbitrary and true hinge axes. J Prosthet Dent. 1980 Mar; 43(3):279-85.
4) Slavicek R. Kriterien der funktionellen Okklusion. Orthod. Und Kieferorthp. 1982, 4: 248.
5) Posselt U. Terminal Hinge Movement of the mandible. J Prosth Dent. 1957, 7:787.
6) Bonwill WGA. Scientific articulation of the human teeth as founded on geometrical, mathematical and mechanical laws. Dental Items Int. 1899 21:617-56, 873-80.
NOTES
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